4.7 Descriptive Statistics in Excel

 Excel provides a convenient tool to compute many of the most commonly used descriptive statistics such as mean, mode, median, variance, and standard deviation all at once.

Example: The following Excel spreadsheet contains some data about life expectancy and literacy rates in about 100 countries of the world in 1995. Compute the mean, mode, median, variance, standard deviation, and range of the two variables.

Life Expectancy Data

First, as usual, we need to load the data into Excel. The spreadsheet should look similar to the following:

 

To compute a variety of descriptive statistics all in one swoop, we proceed as follows:

Make sure that you also check the box "Labels in First Row", then click on "OK".

We can see, for example, that for the average "Life Expectancy" we have computed the mean to be 67.48, the median to be 71, and the mode to be 76. The standard deviation is 9.96, the variance is 99.14 and the range is 37.

These descriptive statistics computed by Excel are familiar, and Excel computes a number of additional values such as range, minimum, etc.,  that are self-explanatory except for "Kurtosis" and "Skewness". We will ignore Kurtosis, but we actually know how to interpret skewness:

Example: Compute the descriptive statistics for the data set

distribution-data.xls

that we analyzed in the previous section about box plots and skewed distributions, and compare the skewness coefficient with the results of your analysis in the previous section.

Loading that data set into Excel and running the "Descriptive Statistics" for all three columns simultaneously yields: